1. Field of the Invention
This invention relates to an apparatus for machining a conical ring, particularly a friction ring, which has inside and ouside conical machinable surfaces having parallel radially aligned generatrices, which apparatus comprises two coaxial machining tools which consist of an outer tool having an inside conical machining surface for machining the outside machinable surface of said ring and an inner tool having an outside conical machining surface for machining said inside machinable surface of said ring, which machining tools are mounted to be rotatable about a common axis relative to said ring and said ring is adapted to be held between said tools so as to be centered on said axis.
2. Description of the Prior Art
To machine the conical friction surfaces of friction ring having a friction lining at least on one of its outside and inside surfaces for use in clutches or brakes, for example, it is known to provide tools which have an outside conical surface that is provided with a diamond-containing coating for polishing the inside friction surface of the conical friction ring. Because the friction ring must be held in position relative to the rotating tool which extends into the opening of the ring, the accuracy of the machining will depend on the centering of the tool relative to the conical ring and on the elastic deformation which is imparted to the ring by the tool. That elastic deformation of the ring adversely affects the accuracy which can be ensured. Similar remarks are applicable to the machining of the outside friction surfaces of a conical friction ring with a tool which comprises an inside conical machining surface for machining the outside friction surface of the ring. Because in a conical friction ring having inside and outside friction linings the tolerances specified for the machining of each friction surface accumulate to a total tolerance, such surfaces cannot be machined to a very high accuracy. Besides, the tool must be fixed in different positions and this involves additional work.